The present invention relates to a charge coupled device. More particularly, the invention relates to a charge coupled device having meandering channel or channels.
In a basic type of charge coupled device, known as a CCD, the gate electrodes, which function to transfer the charge, are linearly arranged. The charge is transferred in the direction of such a gate electrode arrangement when pulse trains of specified waveform and different phases are applied to the device. A CCD of this type has a longer electrode arrangement line almost in proportion to the number of transfer stages. Therefore, when the charge is transferred via many stages, the outer form of device is very narrow and long.
On the other hand, a CCD of two-dimensional type, in which the gate electrodes are arranged in the form of matrix, is also well known. In the two-dimensional type, however, all the electrodes in the same column are connected and are always maintained at the same potential. For this reason, in the two-dimensional type, it is impossible to transfer the charge in the direction of a column, and the transfer is always performed in the direction of a row. The charge transfer is performed simultaneously for all the rows.
In any of the aforedescribed types of CCDs, it is very difficult to change the transfer direction by bending a channel at its halfway point. Thus, for example, when the channel is slightly bent in the same direction each time the charge is transferred for one stage, and this is attempted for a plurality of stages, the transfer direction may ultimately be changed to a desired angle such as, for example, 180.degree.. However, this method requires too large substrate area. Furthermore, the configuration of a transversal filter using a CCD of the type in which the transfer direction is bent complicates the wiring pattern and manufacturing process.
The principal object of the invention is to provide a charge coupled device which overcomes the disadvantages of charge coupled devices of known type.
An object of the invention is to provide a charge coupled device of simple structure, having a channel corresponding to that obtained by bending a single meandering channel 180.degree. at a desired point.
Another object of the invention is to provide a charge coupled device which is inexpensive in manufacture, and the bending angle of which may be readily changed to less than 180.degree., for example to 90.degree..
Still another object of the invention is to provide a charge coupled device having a channel shape which may form a square route, as a whole, by bending the channel 90.degree. in almost equal lengths at four points.
Yet another object of the invention is to provide a charge coupled device in which a signal may be extracted from the side of the channel or injected in the side of the channel with facility.
Another object of the invention is to provide a charge coupled device of very compact structure.
Still another object of the invention is to provide a charge coupled device in which the channel is easily bent and the bus lines and gate electrodes are simple in form whereby the manufacturing process is simplified.
Yet another object of the invention is to provide a charge coupled device of simple structure, which is inexpensive in manufacture, and which functions efficiently, effectively and reliably without the need for a large substrate area for bending.